Playing teams less frequently, and mixing in teams with less tradition. Playing other teams 1/8 of the time is a stupid recipe for a conference that wants to maintain even minor rivalry/emnity between its members (think Michigan-Wisconsin, etc). Why should I root for the conference if it's Syracuse playing some team I don't care about?
If we added ND/Texas/Nebraska to make it a 14 team conference, I'd be okay with that (and that won't ever happen). Anything less, and I'd miss the teams we currently play, even if they are a bit worse than their replacements. Minnesota may be a pretty bad team a lot of the time, but there's history there; replacing it with money is a shitty substitute.